Creating a metric for "% one-touch resolution"

I am trying to build a metric that will give me a percentage of the tickets solved with a single reply. We wish to exclude all tickets solved with 0 touches, so basically I am trying to write a metric that says "The number of tickets solved with one touch divided by all tickets solved with one touch or more". If we have 10 tickets solved with one touch, and 40 solved with one or more touches, it should return the number 25%.

I've tried adding parentheses and rephrasing the metric (for example using the Fact "Ticket replies" or the metric "# Replies" (without the Avg)) but it keeps requesting I rephrase my custom metric. What is the cause, and how should I rephrase it so that I can calculate the % of one-touch resolution this way?

The good news is that this metric already exists within Explore and you wouldn't need to create a custom metric. All you'll need to do is search "One -Touch Tickets" and it should show you the base metric and a % based metric.